To withdraw groundwater stored in both types of aquifers, people dig wells. Unfortunately, the rate of recharge for most groundwater aquifers is much slower than the rate of withdrawal through wells to meet human water needs. As a result, many existing wells are now dry wells, where no more water can be drawn, and cones of depression form in the water table. A cone of depression is an area where the water table dips because water has been withdrawn from that area of the aquifer faster than it could be recharged (see Figure 9-3).